Before taking fish oil, I felt that problems were hard to resolve because they 'stuck' on me. I would ruminate over it and it takes a long time for me to get over it. With fish oil, my brain is less agitated and generally my skin becomes clearer too. I don't brood that much and problems seem to slip right off me. Read this BBC article to learn more about Fish oil and depression.
Fish oil contains two substances that is known to be good for patients. It has Omega 3 fatty acids - EPA and DHA. You might find DHA a familiar term if you give milk formula to young children. They add DHA because it nourishes the brain and supposedly makes them smarter. I'm not advertising on their behalf so I say 'supposedly'. I am, though, convinced by my own experience that EPA and DHA does play a big role in keeping me in the right state of mind. WebMD has a good article about this.